Background: The association of in vitro resistance with bacteriologic, clinical, and health-related quality of life (HRQoL) outcomes for acute uncomplicated cystitis is unclear.
Methods: We conducted a prospective study of women aged 18-40 years with acute uncomplicated cystitis symptoms for ≤7 days who subsequently grew an Enterobacteriaceae sp. and initially received trimethoprim/sulfamethoxazole (TMP/SMX) and phenazopyridine. We conducted telephone follow-up evaluating clinical cure at 1-3 days and in-person follow-up evaluating clinical, bacteriologic, and HRQoL outcomes at 3-7 days and 4-6 weeks post-treatment.
Results: An Enterobacteriaceae sp. was isolated in 139 (96.5%) patients (25.2% TMP/SMX-resistant). At 1-3 days post-treatment, clinical cure occurred in 56/81 (69.1%) and 14/31 (45.2%) of cases with susceptible and resistant strains, respectively (difference 23.9%; 95% confidence interval [CI], 1.5-46.4%). At 3-7 days post-treatment, bacteriologic cure occurred in 70/73 (95.9%) and 15/25 (60%) of cases with susceptible and resistant strains, respectively (difference 35.9%; 95% CI, 13.5-58.3%). Sustained clinical cure rates at 3-7 days and 4-6 weeks post-treatment were 65.4 and 56.8% with susceptible strains, and 45.2 and 45.2% with resistant strains, respectively. The HRQoL scale assessing role limitations due to physical health problems was lower in TMP/SMX-resistant versus TMP/SMX-susceptible infections, with twice as many hours of missed activities reported (mean, 18.4 vs. 9.1 h). Differences in HRQoL appeared to be largely related to differences in clinical cure rates.
Conclusions: Among women treated for acute uncomplicated cystitis with TMP/SMX, in vitro TMP/SMX resistance was associated with lower bacteriologic and clinical cure rates, and had greater impact on the time lost from daily activities compared to those with TMP/SMX-susceptible infections.